The difference between passive house certified windows and passive house certified windows

A huge Irish window manufacturer is not getting tired of screaming out the supply of 5 passive house certified window
systems. That sounds great, but what does it mean?

Unfortunately it means only that the passive house certified window system meets the criterias for a passive house window as
tested in the laboratory. One important point was absolutely not mentioned or tested for the certification - the proper fitting.

To get an idea how important the fitting is, just have a look on the photo above. I´m 100% sure that the triple-glazed
window with a 90mm thick window frame is totally suitable for a passive house. But as long as the connection joints arround the window are too slim (less than 10mm) to insulate them properly and
the window is only superimposed on a concrete window sill, without a working insulation between the sill and the window frame, it is absolutely pointless to celebrate passive house certified
window systems. At the end of the day, the quality of fitting (and sealing) the windows is almost same important as the quality of the window itself.